For the present, the acquisition and processing units for biological signals are made of several interfaces connected to a centralizing system for the management of the alarms and the visualization of the signals or data resulting from the processing of the signals.
FIG. 1 of the accompanying drawings is a block-diagram illustrating an embodiment of such a system according to the present state of the art. To each sensor (electrocardiographic signal sensor-electrodes E; blood-pressure sensor C.sub.P ; temperature sensor C.sub.T, etc. . . . ) is affected an interface, respectively I.sub.ECG, I.sub.P, I.sub.T, . . . I.sub.n, and the interfaces are connected to the centralizing system which is in turn connected for example to a visualization display screen V.
In this known system, each interface is specific to a particular sensor and includes electronic elements providing the amplification, the insulation and various processings particular to the sensor in question. Said sensor is connected to said interface via a terminal provided with a fool-proof device to avoid connection errors when using several interfaces on the same unit.
In order to make such acquisition and processing units more flexible in use, the manufacturers have integrated on some systems interchangeable modules: an acquisition unit comprising four channels for example can be configurated to the requirements of the user as a function of the needs of the patient under supervision.
This relatively stabilized technique does not only offer advantages. Indeed:
(1) It is very costly: the manufacture of the module acquisition system is more complex than a frozen system (also called "compact"). To it have to be integrated:
the mechanical elements ensuring the fixation of the modules, PA1 the connectors providing the connection between the system and each module, PA1 a very flexible management system adapted for displaying on the screen the data relative to each possible module.
Moreover, the user has to have at his disposal a large number of modules for being able to use his systems in an optimal way.
(2) The module housings are dust-traps:
Each acquisition system is seldom loaded with all its modules. The empty compartments provide an access to the connection system, to support rails difficult to clean and possibly to sterilze. Such comparments are seldom closed in practice and they become dust-traps, badly accepted in medical environments.
(3) The management of the modules by the department using them is sometimes difficult since some particular modules may be insufficient in number if several patients are suffering from a pathology necessitating the use of one of said modules.